You know, since I live in the land of tree huggers and granola eaters, I often take it for granted that I can find this stuff in all the grocery stores around here, but if they don't have it in a health-food section (it's refrigerated, so you'd need to look for a small case or maybe they'd stock it somewhere near the yogurt/keffir), you should be able to find it in a health-food store or Whole Foods type place. It's very tart, I have to warn you (I always get the blueberry flavored one, but some of them have other flavors, I figure if I'm going to pucker up like that, I want it to be something I like), but that stuff has kind of almost literally saved my life. No one told me about the damage antibiotics could do the first few dozen times I took them, and I was so depleted from intestinal distress that I was nearly passing out. Fermented foods in general are really good at this time--keffir, and yogurt, obvy, and things like kombucha drinks (which are not the miracle cure their fans like to say they are, but they are helpful) or even stuff like kimchi and sauerkraut! Basically anything that will help you get the good flora back. And of course fibery foods, like some apples and such, can assist.